They need a carbohydrate source.
Dietary fibre is a heterogeneous group of compounds, principally indigestible carbohydrates of plant origin that include NSP, starches that escape digestion in the small intestine (resistant starches, RS) and oligosaccharides.
Previous analyses also indicated that similar families of glycosyl hydrolases were present in the infant and adult gut microbiota, including enzymes that degrade carbohydrates of plant origin (Kurokawa et al. 2007).
In addition, the human gut overrepresented G COGs also include 13 COGs (group II) encoding proteins specialized for the transport and metabolism of carbohydrates of plant origin (table S2, Supplementary Material online).
The common ancestor would have evolved in an environment where various carbohydrates from plant origin constituted the main carbon sources, as can be deduced from the presence of (remnants of) genes involved in their fermentation in the various strains analyzed.
As M4 included functionally diverse glycan degradation families, and had the lowest precision (82.1%) of all modules for lignocellulose degraders, these assignments probably reflect a general ability of the respective organisms to degrade carbohydrate substrates of plant origin.
In this connection, we have conducted several site-specific chemical modification studies with human lysozyme for the purpose of both the alteration of substrate specificity [ 12] and the clarification of the origin of carbohydrate recognition specificity [ 13].
Its high Tm (84 °C) and long activity half-life at elevated temperatures (t1/260 °C > 24 h) make it the most thermostable carbohydrate oxidase of bacterial origin described to date.
The other two HGTs in the AOS were endoglucanase (OG5_137267) of bacterial origin, and carbohydrate-binding protein (OG5_136547), transferred from fungi (supplementary figs. S5 and S6, Supplementary Material online).
However, we believe that the correlations observed support our conclusions reasonably well and that it is plausible that the changes in the GIT microbiota capacity to metabolize carbohydrates may be an origin factor to develop obesity, which in turn may be preventable at a higher level than previously thought.
Essentially, these materials may bring together the intrinsic functionalities of inorganic nanoparticles and the biointerfaces offered by biomolecules and polymers of natural origin, such as carbohydrates and derivatives, glycoconjugates, proteins, DNA, enzymes and oligopeptides [3 5].
